Off-Road Front Suspension System

ABSTRACT

A suspension is provided for coupling a front wheel with a chassis of an off-road vehicle. The suspension comprises upper and lower suspension arms that each includes two inboard mounting points to the chassis and one outboard rod-end joint to a spindle assembly coupled with the front wheel. A ball comprising each outboard rod-end joint is fastened by way a bolt between a pair of parallel prongs extending from the spindle assembly. The upper suspension arm is configured to facilitate coupling a strut between the lower suspension arm and the chassis. A steering rod is coupled with the spindle assembly by way of a steering rod-end joint that is disposed forward of a drive axle, thereby decreasing leverage of the front wheel on the steering rod and substantially eliminating bump steer that may occur due to rough terrain.

PRIORITY

This application claims the benefit of and priority to U.S. ProvisionalApplication, entitled “Off-Road Front Suspension System,” filed on Apr.3, 2017 and having application Ser. No. 62/480,960.

FIELD

The field of the present disclosure generally relates to vehiclesuspension systems. More particularly, the field of the inventionrelates to an off-road front suspension system configured to improve themechanical strength and performance of off-road drivetrains.

BACKGROUND

A double wishbone suspension is a well-known independent suspensiondesign using upper and lower wishbone-shaped arms to operably couple afront wheel of a vehicle. Typically, the upper and lower wishbones orsuspension arms each has two mounting points to a chassis of the vehicleand one mounting joint at a spindle assembly or knuckle. A shockabsorber and a coil spring may be mounted onto the wishbone to controlvertical movement of the front wheel. The double wishbone suspensionfacilitates control of wheel motion throughout suspension travel,including controlling such parameters as camber angle, caster angle, toepattern, roll center height, scrub radius, scuff, and the like.

Double wishbone suspensions may be used in a wide variety of vehicles,including heavy-duty vehicles, as well as many off-road vehicles, asshown in FIG. 1. FIG. 1 shows an off-road vehicle 100 that is of a Sideby Side variety. The Side by Side is a four-wheel drive off-road vehiclethat typically seats between two and six occupants, and is sometimesreferred to as a Utility Task Vehicle (UTV), a Recreational Off-HighwayVehicle (ROV), or a Multipurpose Off-Highway Utility Vehicle (MOHUV). Inaddition to the side-by-side seating arrangement, many UTVs have seatbelts and roll-over protection, and some may have a cargo box at therear of the vehicle. A majority of UTVs come factory equipped with hardtops, windshields, and cab enclosures.

The double-wishbone suspension often is referred to as “double A-arms”,although the arms may be A-shaped, L-shaped, J-shaped, or even a singlebar linkage. In some embodiments, the upper arm may be shorter than thelower arm so as to induce negative camber as the suspension jounces(rises). Preferably, during turning of the vehicle, body roll impartspositive camber gain to the lightly loaded inside wheel, while theheavily loaded outer wheel gains negative camber.

The spindle assembly, or knuckle, is coupled between the outboard endsof the upper and lower suspension arms. In some designs, the knucklecontains a kingpin that facilitates horizontal radial movement of thewheel, and rubber or trunnion bushings for vertical hinged movement ofthe wheel. In some relatively newer designs, a ball joint may bedisposed at each outboard end to allow for vertical and radial movementof the wheel. A bearing hub, or a spindle to which wheel bearings may bemounted, may be coupled with the center of the knuckle.

Constant velocity (CV) joints allow pivoting of the suspension arms andthe spindle assembly, while a drive shaft coupled to the CV jointdelivers power to the wheels. Although CV joints are typically used infront wheel drive vehicles, off-road vehicles such as four-wheeledbuggies comprise CV joints at all wheels. Constant velocity jointstypically are protected by a rubber boot and filled with molybdenumdisulfide grease.

Given that off-road vehicles routinely travel over very rough terrain,such as mountainous regions, there is a desire to improve the mechanicalstrength and performance of off-road drivetrain and suspension systems,while at the same reducing the mechanical complexity of such systems.

SUMMARY

A suspension is provided for coupling a front wheel with a chassis of anoff-road vehicle. The suspension comprises an upper suspension arm thatincludes two inboard mounting points to the chassis and one outboardrod-end joint to a spindle assembly coupled with the front wheel. Alower suspension arm comprises two inboard mounting points to thechassis and one outboard rod-end joint to the spindle assembly. Eachoutboard rod-end joint includes a ball that is rotatable within a casingthat is threadably coupled with each of the upper and lower suspensionarms. A bolt fastens each of the balls between a pair of parallel prongsextending from the spindle assembly, such that the upper and lowersuspension arms may pivot with respect to the spindle assembly duringvertical motion of the spindle assembly, as well as during horizontalrotation of the spindle assembly due to steering. A strut comprising ashock absorber and a coil spring is coupled between the lower suspensionarm and the chassis. The upper suspension arm is configured tofacilitate coupling the strut between the lower suspension arm and thechassis. A steering rod is coupled with the spindle assembly by way of asteering rod-end joint that is disposed at a front of the spindleassembly. The steering rod-end joint includes a ball that is rotatablewithin a casing that is threadably coupled with the steering rod. A pairof parallel prongs and a bolt hingedly couple the steering rod-end withthe spindle assembly, such that the steering rod-end joint allowsvertical and horizontal rotational motion of the spindle assembly duringoperation of the off-road vehicle. The steering rod-end joint is coupledwith the spindle assembly forward of a drive axle, thereby decreasingleverage of the front wheel on the steering rod and substantiallyeliminating bump steer that may occur due to rough terrain.

In an exemplary embodiment, a suspension for coupling a front wheel witha chassis of an off-road vehicle comprises: an upper suspension armcomprising two inboard mounting points to the chassis and one outboardrod-end joint to a spindle assembly coupled with the front wheel; alower suspension arm comprising two inboard mounting points to thechassis and one outboard rod-end joint to the spindle assembly; a strutcomprising a shock absorber and a coil spring that are coupled betweenthe lower suspension arm and the chassis; and a steering rod that iscoupled with the spindle assembly by way of a steering rod-end jointdisposed at a front of the spindle assembly.

In another exemplary embodiment, the strut is mounted to the lowersuspension arm by way of a lower pivot, and an upper pivot couples a topof the strut to the chassis. In another exemplary embodiment, the strutis configured to control vertical articulation of the front suspensionsystem due to movement of the front wheel in response to terrain. Inanother exemplary embodiment, the upper suspension arm may be suitablyconfigured to facilitate coupling the strut between the lower suspensionarm and the chassis. In another exemplary embodiment, the uppersuspension arm is configured in the form of a J-arm.

In another exemplary embodiment, a drive axle including a constantvelocity (CV) joint is coupled between a transaxle and the front wheel,the drive axle being configured to conduct torque from the transaxle tothe front wheel, the CV joint being configured to allow uninterruptedtorque transmission from the transaxle to the front wheel duringvertical pivoting of the upper suspension arm and the lower suspensionarm due to road conditions. In another exemplary embodiment, each of theoutboard rod-end joints includes a ball that is rotatable within acasing that is threadably coupled with each of the upper suspension armand the lower suspension arm. In another exemplary embodiment, a boltfastens the ball between a pair of parallel prongs that extend from thespindle assembly, a recess being disposed between the pair of parallelprongs and having a shape and a size that are suitable to fixedlyreceive the ball and allow a desired degree of movement of the casing onthe ball. In another exemplary embodiment, each of the balls isconfigured to rotate within its respective casing, such that the uppersuspension arm and the lower suspension arm may pivot with respect tothe spindle assembly during vertical motion of the spindle assembly, andsuch that the spindle assembly may undergo horizontal rotation withrespect to the upper suspension arm and the lower suspension arm duringsteering. In another exemplary embodiment, the pair of parallel prongsand the bolt are configured to provide a two-shear joint that maywithstand twice the incident force than may be withstood by asingle-shear joint.

In another exemplary embodiment, the steering rod-end joint includes aball that is rotatable within a casing that is threadably coupled withthe steering rod. In another exemplary embodiment, a pair of parallelprongs and a bolt hingedly couple the steering rod-end with the spindleassembly, such that the steering rod-end joint allows vertical andhorizontal rotational motion of the spindle assembly during operation ofthe off-road vehicle. In another exemplary embodiment, the steeringrod-end joint is coupled with the spindle assembly forward of a driveaxle, thereby providing a front steering system that advantageouslydecreases leverage of the front wheel on the steering rod andsubstantially eliminates bump steer that may occur due to rough terrain.

In an exemplary embodiment, a suspension for coupling a front wheel witha chassis of an off-road vehicle comprises: an upper suspension armcoupled to a spindle assembly by an outboard rod-end joint and coupledto the chassis by at least one or more inboard mounting points; a lowersuspension arm coupled to the spindle assembly by an outboard rod-endjoint and coupled to the chassis by at least one or more inboardmounting points; a strut coupled between the lower suspension arm andthe chassis; and a steering rod coupled to a front of the spindleassembly by a steering rod-end joint.

In another exemplary embodiment, the strut includes a shock absorber anda coil spring that are configured to dampen vertical motion between thechassis and the front wheel in response to terrain. In another exemplaryembodiment, the spindle assembly includes one or more roller bearingsthat support at least a constant velocity joint and the front wheel suchthat uninterrupted torque may be transmitted from a transaxle to thefront wheel during vertical and horizontal movement of the spindleassembly with respect to the chassis.

In another exemplary embodiment, the outboard rod-end joint includes aball mounted within a clevis comprising the spindle assembly androtatably disposed within a casing that is coupled with a suspensionarm. In another exemplary embodiment, the clevis comprises parallelprongs extending from the spindle assembly and a bolt disposed acrossthe parallel prongs, such that the ball may be fixated on the boltbetween the parallel prongs. In another exemplary embodiment, theparallel prongs are configured such that a recess between the parallelprongs has a shape and size that are suitable to receive the ball andallow a desired degree of movement of the casing on the ball. In anotherexemplary embodiment, the clevis is configured to support the ball so asto provide a two-shear joint.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings refer to embodiments of the present disclosure in which:

FIG. 1 illustrates an exemplary embodiment of an off-road vehicle thatis particularly suitable for implementation of an off-road frontsuspension system in accordance with the present disclosure;

FIG. 2 illustrates a front view of a front suspension system that isconfigured to couple a front wheel with a passenger side of an off-roadvehicle; and

FIG. 3 illustrates a front view of an exemplary embodiment of outboardrod-end joints coupling a spindle assembly with upper and lowersuspension arms.

While the present disclosure is subject to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Theinvention should be understood to not be limited to the particular formsdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure. Itwill be apparent, however, to one of ordinary skill in the art that theinvention disclosed herein may be practiced without these specificdetails. In other instances, specific numeric references such as “firstjoint,” may be made. However, the specific numeric reference should notbe interpreted as a literal sequential order but rather interpreted thatthe “first joint” is different than a “second joint.” Thus, the specificdetails set forth are merely exemplary. The specific details may bevaried from and still be contemplated to be within the spirit and scopeof the present disclosure. The term “coupled” is defined as meaningconnected either directly to the component or indirectly to thecomponent through another component. Further, as used herein, the terms“about,” “approximately,” or “substantially” for any numerical values orranges indicate a suitable dimensional tolerance that allows the part orcollection of components to function for its intended purpose asdescribed herein.

In general, the present disclosure describes a suspension for coupling afront wheel with a chassis of an off-road vehicle. The suspensioncomprises an upper suspension arm that includes two inboard mountingpoints to the chassis and one outboard rod-end joint to a spindleassembly coupled with the front wheel. A lower suspension arm comprisestwo inboard mounting points to the chassis and one outboard rod-endjoint to the spindle assembly. Each outboard rod-end joint is comprisedof a ball that is rotatable within a casing that is threadably coupledwith each of the upper and lower suspension arms. A bolt fastens each ofthe balls between a pair of parallel prongs extending from the spindleassembly, such that the upper and lower suspension arms may pivot withrespect to the spindle assembly during vertical motion of the spindleassembly, as well as during horizontal rotation of the spindle assemblydue to steering. A strut comprising a shock absorber and a coil springis coupled between the lower suspension arm and the chassis. The uppersuspension arm is configured to facilitate coupling the strut betweenthe lower suspension arm and the chassis. A steering rod is coupled withthe spindle assembly by way of a steering rod-end joint that is disposedat a front of the spindle assembly. The steering rod-end joint iscomprised of a ball that is rotatable within a casing that is threadablycoupled with the steering rod. A pair of parallel prongs and a bolthingedly couple the steering rod-end with the spindle assembly, suchthat the steering rod-end joint allows vertical and horizontalrotational motion of the spindle assembly during operation of theoff-road vehicle. The steering rod-end joint is coupled with the spindleassembly forward of a drive axle, thereby decreasing leverage of thefront wheel on the steering rod and substantially eliminating bump steerthat may occur due to rough terrain.

FIG. 1 shows an off-road vehicle 100 that is particularly suitable forimplementation of an off-road front suspension system in accordance withthe present disclosure. As disclosed hereinabove, the off-road vehicle100 generally is of a Utility Task Vehicle (UTV) variety that seats twooccupants, includes a roll-over protection system 104, and may have acab enclosure 108. Rear wheels 112 of the off-road vehicle 100 may beoperably coupled with a chassis 116 by way of a trailing arm suspensionsystem. Front wheels 120 may be operably coupled with the chassis 116 byway of the front suspension system disclosed herein. It should beunderstood, however, that the front suspension system of the presentdisclosure is not to be limited to the off-road vehicle 100, but ratherthe front suspension system may be incorporated into a wide variety ofoff-road vehicles, other than UTVs, without limitation.

FIG. 2 illustrates a front view of a front suspension system 124 that isconfigured to couple the front wheel 120 with a passenger side of theoff-road vehicle 100. The front suspension system 124 is comprised of anupper suspension arm 128 and a lower suspension arm 132 that couple thefront wheel 120 with the chassis 116. Each of the upper and lowersuspension arms 128, 132 comprises two inboard mounting points 136 tothe chassis 116 and one outboard mounting joint to a spindle assembly140. As will be recognized, the upper and lower suspension arms 128, 132generally are of a double wishbone variety of suspension thatfacilitates controlling various parameters affecting the orientation ofthe wheel 120 with respect to the off-road vehicle 100, such as, by wayof non-limiting example, camber angle, caster angle, toe pattern, rollcenter height, scrub radius, and scuff.

It should be understood that although the front suspension system 124 isdisclosed specifically in connection with the passenger side of theoff-road vehicle 100, a driver side front suspension system is to becoupled with a driver side of the off-road vehicle. It should be furtherunderstood that the driver side front suspension system is substantiallyidentical to the front suspension system 124, with the exception thatthe driver side front suspension system is configured specifically tooperate with the driver side of the off-road vehicle 100. As will beappreciated, therefore, the driver side front suspension system and thefront suspension system 124 may be configured as reflections of oneanother across a longitudinal midline of the off-road vehicle 100.

As shown in FIG. 2, a strut 144 that is comprised of a shock absorberand a coil spring is mounted to the lower suspension arm 132 by way of alower pivot 148. An upper pivot (not shown) couples a top of the strut144 to the chassis 116. The strut 144 is configured to control verticalarticulation of the front suspension system 124 due to movement of thefront wheel 120 as the off-road vehicle 100 travels over bumpy terrain.The upper suspension arm 128 may be suitably configured, such as in theform of a J-arm, so as to facilitate coupling the strut 144 between thelower suspension arm 132 and the chassis 116 in lieu of being coupledbetween the upper suspension arm and the chassis.

In some embodiments, coupling the strut 144 with the lower suspensionarm 132 positions the strut at between 8 inches and 10 inches lower,with respect to the chassis 116, than the position of the strut whencoupled with the upper suspension arm 128. Experimental observation hasshown that the lower position of the strut 144 generally facilitates alower center of gravity of the off-road vehicle 100 and a relativelysmaller shock angle, as well as eliminating a need for extending thestrut towers through and above a hood of the off-road vehicle 100. Inone embodiment, the coupling of the strut 144 with the lower suspensionarm 132 positions the strut at substantially 90-degrees with respect tothe lower pivot 148 and the upper pivot during full compression of thestrut.

As shown in FIG. 2, a drive axle 146 is coupled between a transaxle andthe front wheel 120. The drive axle 146 is configured to conduct torquefrom the transaxle to the front wheel 120 and accommodate verticalpivoting motion of the front suspension assembly 124 in response to roadconditions. As best shown in FIG. 3, the drive axle 146 is comprised ofa constant velocity (CV) joint 152 that is coupled with the spindleassembly 140 onto which the front week is mounted. The CV joint 152allows uninterrupted torque transmission from the transaxle to the frontwheel 120 during vertical pivoting of the front suspension assembly 124due to road conditions. As will be appreciated, the spindle assembly 140generally supports the CV joint 152 and the front wheel 120 by way ofone or more roller bearings (not shown).

As further shown in FIG. 3, the spindle assembly 140 is pivotallycoupled with the upper and lower suspension arms 128, 132. An upperrod-end joint 156 couples the upper suspension arm 128 to the spindleassembly 140, and a lower rod-end joint 160 couples the lower suspensionarm 132 to the spindle assembly. Preferably, the upper and lower rod-endjoints 156, 160 are of a Heim joint variety, wherein each of the jointsis comprised of a ball 164 that is movable within a casing 168 that isthreadably coupled with each of the suspension arms 128, 132. A bolt 172fastens each of the balls 164 between a pair of parallel prongs 176extending from the spindle assembly 140. It is contemplated that arecess 180 disposed between each pair of parallel prongs 176 has a shapeand a size that are suitable to fixedly receive the ball 164 and allowfor a desired degree of movement of the casing 168 on the ball. Thus,during vertical motion of the spindle assembly 140, as well as duringhorizontal rotation of the spindle assembly 140 due to steering, theballs 164 rotate within their respective casings 168, allowing the upperand lower suspension arms 128, 132 to pivot with respect to the spindleassembly 140.

Upon inspection of FIG. 3, it will be recognized that the upper andlower rod-end joints 156, 160 are similar to Clevis fasteners. Forexample, each pair of parallel prongs 176 is similar to a Clevis, thebolt 172 is similar to a Clevis pin, and the ball 164 and casing 168 aresimilar to a tang. As such, each of the upper and lower rod-end points156, 160 provides two shear planes that may withstand twice the incidentforce that may be withstood by single shear joints that are used inconventional front suspensions.

In the embodiment illustrated in FIG. 3, a steering rod 184 couples thespindle assembly 140 with a steering system of the off-road vehicle 100.The steering rod 184 is coupled with the spindle assembly 140 by way ofa rod-end joint 188 that is similar to the upper and lower rod-endjoints 156, 160. It is contemplated, therefore, that the rod-end joint188 may be of the Heim joint variety or may be of a bushing variety, asdesired. A pair of parallel prongs 192 and a bolt 196 hingedly couplethe steering rod 184 with the spindle assembly 140. As will beappreciated, the rod-end joint 188 allows vertical and horizontalrotational motion of the spindle assembly 140 during operation of theoff-road vehicle 100. Further, the rod-end joint 188 is coupled with thespindle assembly 140 forward of the drive axle 146, thereby providing afront steering system to the off-road vehicle 100. Experimentation hasdemonstrated that the front steering system shown in FIG. 3advantageously decreases leverage of the front wheel 120 on the rod-endjoint 188 and the steering rod 184, thereby substantially eliminatingbump steer that may occur due to forces exerted on the front wheel byrough terrain.

While the invention has been described in terms of particular variationsand illustrative figures, those of ordinary skill in the art willrecognize that the invention is not limited to the variations or figuresdescribed. In addition, where methods and steps described above indicatecertain events occurring in certain order, those of ordinary skill inthe art will recognize that the ordering of certain steps may bemodified and that such modifications are in accordance with thevariations of the invention. Additionally, certain of the steps may beperformed concurrently in a parallel process when possible, as well asperformed sequentially as described above. To the extent there arevariations of the invention, which are within the spirit of thedisclosure or equivalent to the inventions found in the claims, it isthe intent that this patent will cover those variations as well.Therefore, the present disclosure is to be understood as not limited bythe specific embodiments described herein, but only by scope of theappended claims.

What is claimed is:
 1. A suspension for coupling a front wheel with achassis of an off-road vehicle, comprising: an upper suspension armcomprising two inboard mounting points to the chassis and one outboardrod-end joint to a spindle assembly coupled with the front wheel; alower suspension arm comprising two inboard mounting points to thechassis and one outboard rod-end joint to the spindle assembly; a strutcomprising a shock absorber and a coil spring that are coupled betweenthe lower suspension arm and the chassis; and a steering rod that iscoupled with the spindle assembly by way of a steering rod-end jointdisposed at a front of the spindle assembly.
 2. The suspension of claim1, wherein the strut is mounted to the lower suspension arm by way of alower pivot, and an upper pivot couples a top of the strut to thechassis.
 3. The suspension of claim 2, wherein the strut is configuredto control vertical articulation of the front suspension system due tomovement of the front wheel in response to terrain.
 4. The suspension ofclaim 1, wherein the upper suspension arm may be suitably configured tofacilitate coupling the strut between the lower suspension arm and thechassis.
 5. The suspension of claim 4, wherein the upper suspension armis configured in the form of a J-arm.
 6. The suspension of claim 1,wherein a drive axle including a constant velocity (CV) joint is coupledbetween a transaxle and the front wheel, the drive axle being configuredto conduct torque from the transaxle to the front wheel, the CV jointbeing configured to allow uninterrupted torque transmission from thetransaxle to the front wheel during vertical pivoting of the uppersuspension arm and the lower suspension arm due to road conditions. 7.The suspension of claim 1, wherein each of the outboard rod-end jointsincludes a ball that is rotatable within a casing that is threadablycoupled with each of the upper suspension arm and the lower suspensionarm.
 8. The suspension of claim 7, wherein a bolt fastens the ballbetween a pair of parallel prongs that extend from the spindle assembly,a recess being disposed between the pair of parallel prongs and having ashape and a size that are suitable to fixedly receive the ball and allowa desired degree of movement of the casing on the ball.
 9. Thesuspension of claim 8, wherein each of the balls is configured to rotatewithin its respective casing, such that the upper suspension arm and thelower suspension arm may pivot with respect to the spindle assemblyduring vertical motion of the spindle assembly, and such that thespindle assembly may undergo horizontal rotation with respect to theupper suspension arm and the lower suspension arm during steering. 10.The suspension of claim 7, wherein the pair of parallel prongs and thebolt are configured to provide a two-shear joint that may withstandtwice the incident force than may be withstood by a single-shear joint.11. The suspension of claim 1, wherein the steering rod-end jointincludes a ball that is rotatable within a casing that is threadablycoupled with the steering rod.
 12. The suspension of claim 11, wherein apair of parallel prongs and a bolt hingedly couple the steering rod-endwith the spindle assembly, such that the steering rod-end joint allowsvertical and horizontal rotational motion of the spindle assembly duringoperation of the off-road vehicle.
 13. The suspension of claim 11,wherein the steering rod-end joint is coupled with the spindle assemblyforward of a drive axle, thereby providing a front steering system thatadvantageously decreases leverage of the front wheel on the steering rodand substantially eliminates bump steer that may occur due to roughterrain.
 14. A suspension for coupling a front wheel with a chassis ofan off-road vehicle, the suspension comprising: an upper suspension armcoupled to a spindle assembly by an outboard rod-end joint and coupledto the chassis by at least one or more inboard mounting points; a lowersuspension arm coupled to the spindle assembly by an outboard rod-endjoint and coupled to the chassis by at least one or more inboardmounting points; a strut coupled between the lower suspension arm andthe chassis; and a steering rod coupled to a front of the spindleassembly by a steering rod-end joint.
 15. The suspension of claim 14,wherein the strut includes a shock absorber and a coil spring that areconfigured to dampen vertical motion between the chassis and the frontwheel in response to terrain.
 16. The suspension of claim 14, whereinthe spindle assembly includes one or more roller bearings that supportat least a constant velocity joint and the front wheel such thatuninterrupted torque may be transmitted from a transaxle to the frontwheel during vertical and horizontal movement of the spindle assemblywith respect to the chassis.
 17. The suspension of claim 14, wherein theoutboard rod-end joint includes a ball mounted within a cleviscomprising the spindle assembly and rotatably disposed within a casingthat is coupled with a suspension arm.
 18. The suspension of claim 17,wherein the clevis comprises parallel prongs extending from the spindleassembly and a bolt disposed across the parallel prongs, such that theball may be fixated on the bolt between the parallel prongs.
 19. Thesuspension of claim 18, wherein the parallel prongs are configured suchthat a recess between the parallel prongs has a shape and size that aresuitable to receive the ball and allow a desired degree of movement ofthe casing on the ball.
 20. The suspension of claim 17, wherein theclevis is configured to support the ball so as to provide a two-shearjoint.